Several reactions are know to occur in the linear sequence of basic myelin protein in the region of residues 90-129 of the bovine protein: the serine at 109 can be phosphorylated by a protein kinase; the threonine at 97 can be glycosylated by a N-acetyl galactosaminyl transferase; arginine at 106 can be methylated by a methylating enzyme to give omega-monomethylarginine or omega-N-N1-dimethylarginine; and the region of 102-121 is proposed as a receptor site for 8-hydroxytryptamine (serotonin). Some or all of this reactivity may be involved in the function of the protein. Since the protein has little tertiary structure, it is proposed that each of these reactions can be studied using isolated peptides containing different areas of the 90-129 sequence. We have demonstrated that the synthetic peptide: Gly-Arg-Gly-Leu-Ser-Leu-Ser-Arg (residues 105-112) can be phosphorylated at serine 109 by a cyclic-AMP dependent protein kinase (Daile, Carnegie and Young, Nature 257:416-418, 1975). We have also demonstrated that the peptide Arg-Pro-Thr-Pro-Pro-Pro can be glycosylated (Fed. Proc. in press, 1978). The specificity of the reactions will be studied by testing the reactions with analogs of the peptides. Solid phage peptide synthetic methods will be utilized in preparing the peptides. The biological testing of the peptides will be performed in our laboratory and the laboratories of Patrick R. Carneigie, Melbourne, Australia and R. Colin Hughes of the British Medical Research Council, Mill Hill, England. The following radioactive compounds will be used in the assays: (32P)-ATP, S-adenosyl (1-methyl 14C)-methionine, UDP-N-acetyl galactosamine (14C) and (14C)-serotonin. A synthetic substrate for studying the N-acetyl galactosaminyl polypeptide transferase enzyme will be useful to Dr. Hughes. He iw setting up a wide panel of assays for investigating the involvement of glycosyl transferase in mental illnesses. The peptides will also be made available for testing their involvement in inducing experimental allergic encephalomyelitis and their use in an assay being investigated for cancer diagnosis.